Because of PR c++/85944 we have several bugs where _GLIBCXX_DEBUG causes
errors for constexpr code. Although Bug 117966 could be fixed by
avoiding redundant debug checks in std::span, and Bug 106212 could be
fixe by avoiding redundant debug checks in std::array, there are many
more cases where the same checks fail and can't be avoided.
This just disables the __gnu_debug::__check_singular(T*) check during
constant evaluation. Attempting to dereference a null pointer will
certainly fail during constant evaluation (or it's a compiler bug and
not the library's problem if it doesn't fail). Disabling this check
shouldn't do any harm.
libstdc++-v3/ChangeLog:
PR libstdc++/109517
PR libstdc++/109976
* include/debug/helper_functions.h (__valid_range_aux): Treat
all input iterator ranges as valid during constant evaluation.
---
Tested x86_64-linux.
libstdc++-v3/include/debug/helper_functions.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/libstdc++-v3/include/debug/helper_functions.h
b/libstdc++-v3/include/debug/helper_functions.h
index d686a29e8ee..8d6a5fb41fb 100644
--- a/libstdc++-v3/include/debug/helper_functions.h
+++ b/libstdc++-v3/include/debug/helper_functions.h
@@ -168,6 +168,11 @@ namespace __gnu_debug
__valid_range_aux(_InputIterator __first, _InputIterator __last,
std::input_iterator_tag)
{
+ // FIXME: The checks for singular iterators fail during constant eval
+ // due to PR c++/85944. e.g. PR libstdc++/109517 and PR libstdc++/109976.
+ if (std::__is_constant_evaluated())
+ return true;
+
return __first == __last
|| (!__gnu_debug::__check_singular(__first)
&& !__gnu_debug::__check_singular(__last));
--
2.47.1
